I think I'm getting the fender mustang II but it have doesn't a mid knob so would it really have a big effect if I play it through my epiphone les paul
So whats the question?
Have a look here : https://www.ultimate-guitar.com/forum/showthread.php?t=1588141

Get a Vox VT or a Peavey Vypyr
You will be fine.
I have a Krank 1980 Jr and the clean ch does not have a mid knob and it sounds great. I use lots of guitars with it and my LP clone sounds great.

You will be fine with the mustangII and a LP
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate